A vehicle side section structure equipped with a vehicle side door having inside a pipe-like impact beam extending in a vehicle front and rear direction is known (e.g., patent document 1). Extensions are welded to both lengthwise direction (vehicle front and rear direction) end portions of the impact beam. The extensions are welded to impact beam attachment portions disposed on a vehicle front and rear direction front end side and rear end side of a door inner panel that configures the vehicle side door.
Patent Document 1: Japanese Patent Application Laid-open (JP-A) No. 2007-203895